Iodinated disinfection byproducts (DBPs) have recently been detected in US drinking water treatment plants using chloramine, a disinfectant replacement for chlorine that was introduced in order to minimize the formation of the four regulated chloro-bromo trihalomethanes (THMs), which are potential human carcinogens. The iodinated THMs and other DBPs in drinking water are more genotoxic and cytotoxic to mammalian cells than the chloro-bromo counterparts. Therefore, their detection and minimization is crucial to protect public health. Our study aims to validate, in our laboratory, sensitive and specific analytical methods for detection of these compounds, to measure their occurrence in chloraminated drinking waters, to determine the potential for their formation in natural waters treated with emergency disinfection iodine tablets, to measure the ability of granular activated carbon filters to remove iodinated DBPs from water, and to identify the potential human health risk associated with use of iodine tablets as a point-of- use strategy for disinfection of drinking water. PUBLIC HEALTH RELEVANCE: Due to their apparent toxicity to humans, the iodinated disinfection byproducts pose a potential public health risk to (1) military troops or Peace Corps volunteers that rely on iodine tablets or iodinated resin filters for drinking water disinfection for long periods of time and (2) coastal communities with drinking water treatment plants that treat their high iodide source water with chloramine disinfection which transforms the iodide to iodine. Our pilot study aims to measure the occurrence of iodinated DBPs in both cases and to identify the potential human health risk associated with these exposures.